Many large rivers are experiencing a significant reduction in sediment flux owing to human activity. Sediment transport capacity directly affects the predictive accuracy of sediment concentration in morphodynamic modelling. A total of 1092 datasets with extremely low sediment concentrations in a quasi-equilibrium state were selected at five hydrometric stations of the Middle Yangtze River, and used

This paper describes a self-similarity-analysis-based inundation process in which the water depth at the inlet increases as a power function of time. Numerical analyses of the inundation process are conducted to evaluate the feasibility and stability of two types of regimes: inertia-pressure regime and pressure-friction regime. Numerical simulations using the shallow water equations are conducted to

Since the 1990s, pressure waves propagating in pressurized pipes during a transient event have been re-evaluated both in the laboratory and in real systems as a way to obtain information about location and size of leaks. However, a systematic analysis of the obtained results has not been offered yet in the literature. In this paper, a review of the available experimental data concerning the use of

ABSTRACT Drop experiments with quartz spheres in a flume setting were performed to investigate the dynamic signal response of the Swiss plate geophone bedload monitoring system for varying particle size, vertical impact velocity, and impact location. For a similar sphere impact set-up, the finite element method was used to determine the propagation characteristics of the stress wave in the structure

Turbulent flow has been known to contain coherent flow structures. The size, shape, timescale and dynamics of these coherent structures are important in understanding turbulent flow processes such as pollutant mixing and particle transport. A range of methods exist for the detection of coherent structures in 2D or 3D data, but there are limited objective methods available for 1D data. Existing 1D techniques

A model based on the exponential function was proposed to predict the velocity fields in partially vegetated channels. Eleven groups of experimental data obtained from this study and the published literature were used to verify the model. The predicted lateral profiles of velocities at different longitudinal positions had good agreement with measurements over wide ranges of flow and vegetation conditions

Sewer pipe pressurization is a phenomenon that can cause structural damage in urban drainage systems and can result in a public health issue, especially in cities that have combined sewer systems. Studies have classified the phenomena of downstream to upstream pressurization in stages, proposing several mathematical models to predict pressure variations and the effect generated by air entrapment. This

Forrest Merton Holly Jr dealt extensively with numerical modelling of unsteady flows and dispersion processes associated with the operation of hydropower and thermal power plants, and often with alluvial sediment transport by rivers. His expertise, energy, and genial personality led him to become President of the International Association of Hydraulic Engineering and Research (IAHR) during 2000–2003

Published in Journal of Hydraulic Research (Ahead of Print, 2022)

A laser profilometry technique was upgraded to detect underwater bed level evolution with a laser and a single camera for highly transient laboratory experiments. The proposed procedure is simple, but achieves a similar performance as that met by more complex and expensive methods. This technique was applied to a dam-break test case over a mobile bed in a channel with a 90° bend, for which water and

This technical note presents results from flume experiments conducted in a straight prismatic asymmetric compound channel with two different floodplain roughnesses and rigid emergent vegetation along the floodplain edge in combination with a mobile and fixed main channel bed, respectively. It is found that the contribution of floodplain roughness and vegetation along the floodplain edge to the bulk

Accurate prediction of levee breach flow is crucial to the mitigation of floods, and for timely breach closure. In this work, flow in an idealized levee breach has been studied for the case of a trapezoidal embankment. Flow data including water depths, surface velocities, and flow discharges were obtained from 28 experiments considering different cases of breach width and main channel downstream water

This study discusses the effects of geometrical parameters of flaring gate piers, such as contraction ratio, sidewall extension ratio and plunge angle, on the impinging pressure and flood atomization based on hydraulic model tests and atomization simulations. It is found that the impinging pressure decreases and the length of rainstorm increases with the increasing impact collision of aerated jets

To demonstrate the influence of cavitation on pressure fluctuation in a pump-turbine, one- and three-dimensional coupling numerical simulations were conducted on a typical runaway process that occurs when the turbine rejects the load. Transient flow in the pipelines was simulated using a one-dimensional single-phase flow model. The unsteady three-dimensional turbulence flow in the pump-turbine was

This technical note presents the DualSPHysics application to spillway hydraulics, and an extensive comparison has been made between the single-water and two-phase water–air modelling approaches. It has been found that the DualSPHysics code based on the smoothed particle hydrodynamics method could provide a promising design tool for spillway flows in the engineering field. The model is first validated

When a river debouches into a shallow receiving basin, it behaves as a sediment-laden shallow jet which plays a key role in the subsequent sediment transport and morphological evolution at the river mouth. A linear stability analysis that directly incorporates the effect of the presence of suspended sediment on the hydrodynamic instability of shallow jets was performed in this study. The sediment effect

Previous studies investigated the flow in a local scour hole mainly from two perspectives, i.e. mean velocity and turbulence, but there is no literature exploring it from the perspective of pressure. This study investigates the dynamic pressure fields in a local scour hole formed by a wall jet using PIV (particle image velocimetry) data to solve the Navier–Stokes (N-S) and Reynolds-averaged Navier–Stokes

Drop manholes are commonly employed to reduce slopes in sewer systems. Diverse particles can enter into these systems and gather in drop manholes where they can chain and clog the outflow. As their residence time in the manhole pool increases, the outlet blockage risk rises. The jet-breaker was used for improving the performance of drop manholes under Regime R2, in which the inlet jet collides with

Current research investigating ice-covered bridge pier scour has focused on the effects of fully developed ice jams. However, based on observations at various stages of development, ice covers are not always fully developed. This experiment investigated pier scour at various stages of a simulated floating ice jam’s development, with a constant flow rate. Various channel-spanning ice cover lengths were

Under a flow in supercritical regime, depending on the pier width to water depth ratio, the flow pattern around a bridge pier can take the form of a wall-jet-like bow wave or a detached hydraulic jump. The present work aims at analysing the maximum scour depth at piers in both flow patterns. A dedicated experimental set-up was used to produce the live-bed scour experiments, varying the inflow velocity

Simulations are performed to investigate gravity currents in the presence of free surface waves using the open-source computational fluid dynamics programme REEF3D with the concentration equation, and the large eddy simulation model for turbulence closure. Simulations show that the period of the oscillation front relates only to the period of the incident waves and the oscillation amplitude increases

Large-eddy simulations (LES) of supercritical flow in a straight-wall, open-channel contraction of 6° and contraction ratio of 2:1 are performed. The LES code solves the filtered Navier-Stokes equations for two-phase flows (water-air) and employs the level-set method. The simulation was validated by replicating a previously reported experiment. Contours of the time-averaged velocities indicate that

Published in Journal of Hydraulic Research (Vol. 60, No. 4, 2022)

(2022). Correction. Journal of Hydraulic Research: Vol. 60, No. 3, pp. 514-514.

This study proposes a scour equation for abutments that is based on a combination of Newton’s second law and a turbulence model comprised of a pair of isotropic vortices. A control volume of the scour hole is considered on which the sum of forces equals nil. The effect of abutments on local scour is usually modelled by an empirical K-factor for which there is no physical description available. Here

In axial flow pump systems, not only are the flow rates typically large but the water leaving the guide vanes almost invariably possesses a residual rotation. Since such pumps often generate only low heads, the energy content of this residual rotation often has a notable influence on the hydraulic and economic performance of the outlet conduit. The hydraulic losses and flow fields associated with a

(2022). Large eddy simulation of sediment transport in high flow intensity by discrete particle method By B. ZHANG, B. WU, S. LI and Y. SHI, J. Hydraulic Res. 59(4), 2020, 605–620, https://doi.org/10.1080/00221686.2020.1818306. Journal of Hydraulic Research: Vol. 60, No. 1, pp. 182-183.

Time reversal of waves is an intriguing wave property that underpins a breadth of applications in physics and engineering. Waves contain information about their sources and the media through which they propagate. Thus, time reversal of measured wave signals has the potential of localizing and characterizing wave sources and of inferring the properties of the medium. Herein, we experimentally demonstrate

Predicting piping failure is essential for assessing dike and dam safety. To improve the current description of internal erosion, we sought to evaluate the effects of laminar and turbulent flow on the transport of particles, which is lacking in existing assessment manuals. These insights are necessary to develop engineering tools to predict piping caused by seepage-induced backward erosion in loose

This paper presents results of a solitary wave propagating over a submerged horizontal plate based on a non-hydrostatic model. A high-resolution advection scheme is employed based on a second-order flux-limiter method. The model is first validated by comparing numerical results with recently obtained measured data. Then, a series of simulations are carried out to investigate the effect of the plate

Tidal stream turbines operate in the harsh marine environment, subjected to turbulence, wave action and wakes from upstream devices when deployed in arrays. Turbines may be mounted on the sea bed or on floating platforms. Numerical models are invaluable to study individual and array performance and their interaction with environmental flows. To date, shallow water models and three-dimensional Reynolds

This work uses the smoothed particle hydrodynamics (SPH) meshless numerical method in order to investigate the behaviour of a water sheet falling under gravity by reproducing the experimental results of a laboratory chute of 9.5 m height. This kind of flow occurs typically over dam ogee-type spillways. The focus is on the trajectory and velocity of the water sheet as well as on the pressure upon impact

This paper outlines the implementation of an efficient implicit method for a free surface boundary for solving free surface flows with larger time steps. In this method, the governing equations are solved with dynamic conditions applied to the free surface boundary. The position and shape of the free surface are represented with adaptive boundary grid points. Unlike existing explicit methods, the proposed

A Large Eddy Simulation of a fully developed turbulent open-channel flow with a Reynolds number of Re=71,755 was performed to study dynamics of coherent structures in the vicinity of a stationary sediment particle. The sediment particle was positioned at the bottom on a smooth channel bed. The impulse concept was employed by computing three-dimensional hydrodynamic forces acting on the sediment particle

Hydraulic vibrations of pipe flow in hydropower stations cause stability and reliability issues, or can result in local damage and operating accidents in hydraulic, structural, mechanical, electrical and associated power systems. Based on a comprehensive analysis focusing on hydraulic vibration in water conveyance system and relevant instability issues, key advances in numerical-based hydraulic vibration

Time reversal (TR) of waves is being used in many fields and underpins the foundation of practical equipment that, for example, is used to destroy brain tumour and kidney stones, to detect defects in solids, to pinpoint underground mineral deposits, and to assist in long-distance communication. Theoretically, the TR property of waves is lost in the presence of damping. However, techniques which are

In this study, a numerical model for river ice dynamics (DEMRICE) based on the discrete element method is developed. The ice dynamic component of this model considers moving surface ice floes as discrete elements. It uses a three-dimensional dilated polyhedral discrete element method to resolve contact and external forces on individual ice floes. The hydrodynamic component uses a streamline upwind

Light floater boards are commonly used in open channel flow studies to reduce free surface disturbances. However, the shear layer generated from the surface of the floaters, which has not been considered in previous research, may have unintended effects, and can alter the downstream flow characteristics. This aspect is investigated using particle image velocimetry at Reynolds number of 35,100 by varying

This paper presents the results of a LES of turbulent surface jets over a submerged weir. The mean flow and turbulent structures are presented for both flat and deformed bed conditions. LES results with the scour hole reveal that the separated shear layer is extended by about three times, locating the reattachment point further downstream. In addition, the presence of the scour hole increases both

The dependency of the friction factor on the flow direction was investigated experimentally in a milled scale model of an unlined rock blasted tunnel under pressurized flow conditions by reversing the flow direction. The experimental data were used to highlight the significance of anisotropic roughness structures and variations in the cross-sectional area on the flow resistance. It is hypothesized

Quasi two dimensional (2D) and one dimensional (1D) numerical simulations of transient flow with column separation are conducted using the discrete vaporous and gaseous cavitation models (DVCM and DGCM) in a simple reservoir-pipeline-valve system. In the quasi 2D transient model, the governing equations are solved by the method of characteristics along the pipe and by finite difference across the pipe

The present study discusses the evolution of bed morphology under 2D dam-break flow by conducting a set of laboratory experiments. The experiments were conducted in a 1.6 m × 28 m × 1.0 m glass flume with non-uniform fly ash as the bed material. Two scenarios were designed: no inflow (scenario 1) and nearly constant water level (scenario 2) in the upstream reservoir. During the experiment, the water

This paper aims to develop a backward analysis version of the inverse transient leak detection method for plastic pipes. To carry out the analysis, the structure of the Kelvin–Voigt model is modified to match the numerical structure of the backward model. Brunone unsteady friction is also discretized to make it correspond to the numerical structure. In order to investigate the performance of the improved

Pre-swirl in the approach flow towards a pump leads to a decreased efficiency or even to malfunctioning of a pump. Especially for pumping stations with large rotodynamic pumps, the risk of malfunctioning should be minimized. For this reason, hydraulic investigations are performed prior to the construction of pumping stations to assess the amount of pre-swirl in the approach flow and if needed, to design

ABSTRACT Scroll vortex intakes are commonly used in water supply, drainage and sewerage systems. Water flows into the intake via an eccentric approach channel, forming a swirling vortex flow with a stable air core along the dropshaft. Previous design theories have largely been based on unjustified assumptions on the velocity and pressure distributions of the vortex flow at the intake bellmouth. To

Self-aeration in open channel flows occurs owing to free surface air entrainment. Self-aeration development and fully cross-sectional distribution of air concentration are not thoroughly understood. In the present study, an analytical solution for the averaged cross-sectional air concentration in the gradually varying region is established using a simplified mechanism of free surface air entrainment

In urban stormwater systems, a rapid increase in water inflow can cause the entrapment of air pockets and subsequent ejection of air/water mixture, commonly known as storm geysers. In this study, a three-dimensional computational fluid dynamics model was built based on a lab model, which consisted of an upstream pipe and a downstream pipe with different invert elevation (i.e. a drop), connected by

The dynamics of sandy rivers is a complex phenomenon linking the interactions between dunes, flow and sediment transport. Despite an existing large amount of research, few comparative studies exist for rivers with major hydro-sedimentological differences. This work uses detailed dune measurements from the Paraná and Tercero rivers, Argentina. Significant differences were found in the representative

A weighting function model was developed to account for the relationship between flow unsteadiness and frictional resistance. The Manning equation cannot fully describe such processes, leading to deficiency in predictive capability under some conditions. Two fundamentally new contributions to our approach are the development of (1) an additional unsteady component using time derivatives of flow-state

ABSTRACT This paper describes the characteristics of the formation of periodic roll waves and the splitting of waves based on nonlinear mode analysis. A novel system is developed to investigate the formation of roll waves through linear and nonlinear modal analyses. The nonlinear analysis shows the feasibility of the periodic roll waves and their splitting when the wavenumber is extremely small. It

A novel analysis method is proposed to evaluate the impact of specified components in a pipe network on the severity of transient events. A new structural scheme for the impedance matrix was developed to ensure the feasibility of compartmental unsteady analyses, which can be useful for complex pipe networks with different pipeline elements. The impact of a specific pipeline element or a designated

Load rejection is one of the most dangerous transients in pumped-storage plants, during which cavitation in pump-turbines is normally inevitable. In this study, we applied the one-dimensional and three-dimensional coupled computational fluid dynamics method to simulate the 100% load rejection transient process of a middle-head plant, analysed the evolution and influence of cavitation cavities, and

On a stepped channel, three distinct flow regimes, nappe, transition, and skimming, occur successively with increasing discharge. This work proposes a criterion of the transition flow occurrence: a critical slope of the channel exists between mild and steep slopes, and for mild slopes, air pocket disappearance and nappe parallel to channel slope are defined as the lower and upper limits of transition

(2021). Computational fluid dynamics for sub-atmospheric pressure analysis in pipe drainage By Mohsen Besharat, Oscar Enrique Coronado-Hernández, Vicente Samuel Fuertes-Miquel, Maria Teresa Viseu and Helena Margarida Ramos, J. Hydraulic Res. 58(4), 2020, 553–565, 10.1080/00221686.2019.1625819. Journal of Hydraulic Research: Vol. 59, No. 6, pp. 1031-1034.

(2021). Closure to “Computational fluid dynamics for sub-atmospheric pressure analysis in pipe drainage” by Mohsen Besharat, Óscar E. Coronado-Hernández, Vicente S. Fuertes-Miquel, Maria Teresa Viseu and Helena Margarida Ramos, J. Hydraulic Res. 58(4), 2020, 553–565, https://doi.org/10.1080/00221686.2019.1625819. Journal of Hydraulic Research: Vol. 59, No. 6, pp. 1034-1035.

(2021). A remark on finite volume methods for 2D shallow water equations over irregular bottom topography By Cristiana Di Cristo, Massimo Greco, Michele Iervolino, Riccardo Martino and Andrea Vacca. Journal of Hydraulic Research: Vol. 59, No. 6, pp. 1036-1037.

(2021). Closure to “A remark on finite volume methods for 2D shallow water equations over irregular bottom topography” by Cristiana Di Cristo, Massimo Greco, Michele Iervolino, Riccardo Martino and Andrea Vacca. Journal of Hydraulic Research: Vol. 59, No. 6, pp. 1038-1039.

(2021). Experimental study on the 3D-flow field of a free-surface vortex using stereo PIV. Journal of Hydraulic Research: Vol. 59, No. 5, pp. 858-859.

(2021). Closure on discussion Experimental study on the 3D-flow of a freesurface vortex using stereo PIV. Journal of Hydraulic Research: Vol. 59, No. 5, pp. 859-861.

Hydropower is a key energy conversion technology for stabilizing electrical power. When running at full load, a 3-D cavitation vortex rope develops in Francis turbines that acts as an internal source of energy and instability. 1-D models allow this phenomenon to be predicted and the range of safe operating points to be defined. These models involve three parameters: the mass flow gain factor, the wave